Color photographic light-sensitive elements

ABSTRACT

BY INCORPORATING A COPOLYMER OF VINYL ALCOHOL AND VINYL PYRROLIDONE, A PARTIALLY SAPONIFICATED POLYVINYL ALCOHOL, OR A COPOLYMER OF VINYL ALCOHOL AND CYANOETHYLVINYL ETHER OR A COPOLYMER OF VINYL ALCOHOL AND ALKYLVINYL ETHER IN A PHOTOGRAPHIC LAYER OF A COLOR PHOTOGRAPHIC LIGHT-SENSITIVE ELEMENT, IN PARTICULAR, A COLOR PHOTOGRAPHIC SILVER HALIDE EMULSION HAVING INCORPORATED THEREIN AN OIL-SOLUBLE COUPLER AND AN OILY SOLVENT HAVING A HIGH BOILING POINT, THE SILVER REMOVAL OR SILVER BLEACHING OF DEVELOPED SILVER IN BLEACHING PROCESS AFTER COLOR DEVELOPMENT IS EFFECTIVELY IMPROVED WHEREBY THE COLOR TURBIDITY OF COLORED IMAGES CAN BE REDUCED.

United States Patent 3,730,726 COLOR PHOTUGRAPHHC LIGHT-SENSITIVE ELEMENTS Nobuo Tsuji, Yoshiaki Ono, Fumihilro Nishio, and Hirozo Ueda, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Minami Ashigara-shi, Kanagawa, Japan No Drawing. Continuation-impart of abandoned applica' tion Ser. No. 717,420, Mar. 29, 1968. This application Sept. 14, 1970, Ser. No. 72,116

Claims priority, application Japan, Mar. 29, 1967, 4Z/19,696, 4-2/19,697, 42/l9,698 Int. Cl. G03: 1/04 US. CI. 96-84 R 11 Claims ABSTRACT OF THE DISCLOSURE By incorporating a copolymer of vinyl alcohol and vinyl pyrrolidone, a partially saponificated polyvinylalcohol, or a copolymer of vinyl alcohol and cyanoethylvinyl ether or a copolymer of vinyl alcohol and alkylvinyl ether in a photographic layer of a color photographic light-sensitive element, in particular, a color photographic silver halide emulsion having incorporated therein an oil-soluble coupler and an oily solvent having a high boiling point, the silver removal or silver bleaching of developed silver in bleaching process after color development is effectively improved whereby the color turbidity of colored images can be reduced.

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation'in-part application of our copending application Ser. No. 717,420, filed Mar. 29, 1968, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates generally to color photography and more particularly to a color photographic lgiht-sensitive element having a photographic layer containing an improved color turbidity-preventing agent.

By color-turbidity is meant the phenomenon caused by poor silver removal after color developing a color photographic light-sensitive element in an oxidizingbleaching bath, whereby a Wide spectral absorption band of the remaining silver overlaps a sharp spectral absorption band of the developed color image. That is, the phenomenon is fundamentally different from so-called fogging, or blacking of the unexposed portions of the light-sensitive element.

The following types of color photographic light-sensitive elements are known which have photographic silver halide emulsion layers containing couplers capable of forming dye images by coupling with the oxidation prodnot of an N,N-dialkyl-p-phenylenediamine developing agent.

In one type of color photographic light-sensitive element, a coupler containing an oil-soluble group in the coupler molecule such that the coupler can be dissolved in a water-immiscible (oily) organic solvent having a high boiling point is dissolved in an oily solvent having a high boiling point. The solution is then dispersed in a gelatin solution containing a dispersing agent such as sodium alkylbenzene sulfonate, and after mixing the dispersion thus prepared with a photographic silver halide emulsion, the resulting mixture is applied to a support.

In another type of color photographic light-sensitive element, an oil-soluble coupler is incorporated in a photographic silver halide emulsion directly without using the aforesaid .water-immiscible organic solvent having a h gh boiling point and the mixture is applied to a support.

In still another type of color photographic light-sensitive element, a water-soluble or alkali-soluble group s incorporated in the long-chain aliphatic hydrocarbon group of a coupler molecule and after adding the coupler directly to a photographic silverhalide emulsion, the resulting emulsion is applied to a support.

One of the difiiculties frequently encountered in these types of color photographic light-sensitive elements is that the colors of dye-images formed therefrom become turbid, the purity of color is deteriorated and the sharpness or clearness of color is lost. This is because the developed silver image, formed during the processing of the color photographic element is insufiiciently removed by an oxidation and bleaching bath after color development to leave the residual developed silver therein. Hence, a spectrally wider light-sensitive absorption band of the residual developed silver superimposes on the sharp spectral absorption band of the dye image.

Various efforts have been made: for preventing the formation of color turbidity in colored images by incorporating a color turbidity preventing agent in a color photographic light-sensitive emulsion to improve the silver removal during the processing. For example, in the specification of Japanese Pat. No. 705/66 it is disclosed that a water-soluble or alkali-soluble homopolymer of vinyl pyrrolidone or copolymer of vinyl pyrrolidone and other monomer incorporated in the emulsion layers is effective as a color turbidity preventing agent. It is disclosed therein that the monomer to be copolymerized with vinyl pyrrolidone may be a vinyl ester (such as vinyl acetate, vinyl propionate, vinyl butyrate, etc.), acrylic ester, methacrylic ester, acrylic acid, methacrylic acid, and styrene. Although the compounds shown in the specification of Japanese Pat. No. 705/66 improve the silver removal there is the added disadvantage that by the addition thereof the development of silver halide is suppressed markedly to prolong the period of time required for finishing the development.

An object of this invention is to provide a color photographic light-sensitive element having little or no residual developed silver image accompanying the dye images after processing to provide more brilliant dye images, and having reduced development suppressing properties.

SUMMARY OF THE INVENTION The inventors have found'that by incorporating (1) a copolymer of vinyl alcohol and vinyl pyrrolidone in a specific monomer ratio, (2) a partially saponificated polyvinyl alcohol, or (3) a copolymer of vinyl alcohol and cyanoethylvinyl ether or a copolymer of vinyl alcohol and alkylvinyl ether in a photographic layer of a color photographic light-sensitive element, in particular, a color photographic silver halide emulsion having incorporated therein an oil-soluble coupler and an oily solvent having a high boiling point, the silver removal or silver bleaching of developed silver in the bleaching process after color development is effectively improved whereby the color turbidity of colored images can be reduced. Also, the suppression of color development is markedly reduced.

3 DETAILED DESCRIPTION OF THE INVENTION According to the present invention there is provided a color photographic light-sensitive element comprising a support bearing thereon photographic silver halide emulsion layers, a protective layer, insulating layers, filter layers, and an antihalation layer, at least one of said photographic layers having incorporated therein either (1) a copolymer of vinyl alcohol and vinyl pyrrolidone represented by the general formula l rho-H2 n (1) wherein the ratio of x to y ranges from 95/5 to 40/ 60, and wherein n is a positive integer of from 400 to 2000; (2) a partially saponificated polyvinyl alcohol represented by the general formula wherein the ratio of x to y ranges from 95/5 to 70/30 and n is a positive integer of from 400 to 2000, or (3) a copolymer of vinyl alcohol and cyanoethylvinyl ether or a copolymer of vinyl alcohol and an alkyl vinyl ether represented by the general formula wherein R represents an alkyl group having 1 to 4 carbon atoms or CH CH CN, the ratio of x to y ranges from 95/5 to 30/70, and wherein n is a positive integer of from 400 to 2000.

The effect of the above-mentioned copolymer of vinyl alcohol and vinyl pyrrolidone depends upon the monomer ratio (x/ y) of the copolymer. The larger the content of vinyl pyrrolidone (y), the higher the silver-removal effect, on the other hand, the smaller the content of vinyl pyrrolidone, the lower the development suppression. Thus, the optimum monomer ratio of x to y is suitably from 95/5 to 40/ 60 and more preferably from 80/20 to 90/10.

The copolymer of vinyl alcohol and vinyl pyrrolidone used in this invention is soluble or can be dispersed in the collodial state in water, alkali or preferably in organic solvents.

The effect of the copolymer of vinyl alcohol and vinyl pyrrolidone used in this invention depends to a certain extent on the degree of polymerization. That is, a copolymer having any degree of polymerization may be employed if it is soluble in water, a liquid or solid having a high boiling point (at least 200 C.). However, the degree of polymerization affects the characteristics of the emulsion and the color turbidity of the yellow image and accordingly, it is preferred that the degree of polymerization ranges from 400 to 2000.

If the saponification value of the above-mentioned partially saponified polyvinyl alcohol used in this invention is too high or too low, the solubility thereof in water or organic solvents becomes poor and hence the color turbidity preventing effect thereof is reduced. Thus, as mentioned above, the suitable ratio of x to y is from 95/5 to 70/30 or more but preferably from 80/20 to 90/ 10.

The partially saponified polyvinyl alcohol used in this invention is water soluble or can be dispersed in the colloidal state in water, alkali or preferably in organic solvents.

The color turbidity-preventing effect of the partially saponified polyvinyl alcohol used in this invention is influenced by the degree of polymerization thereof. Too low a degree of polymerization may cause the color turbidity-preventing effect to be reduced during storage, while o h a deg ee Qt r ymsriaa iq m y result i the reduced solubility of the polymer in water or in organic solvents. Thus, a suitable degree of polymerization is from 400 to 2000 as mentioned above or most preferably from 500 to 1000.

Furthermore, as mentioned above the color turbiditypreventing agent of this invention may be a copolymer of vinyl alcohol and cyanoethylvinyl ether or a copolymer of vinyl alcohol and an alkyl vinyl ether. In this case, although the color turbidity-preventing effect of the copolymers is not greatly influenced by the monomer ratio in the copolymers, too small a proportion of vinyl alcohol may cause a reduction in the fixing rate of silver halide during processing. Thus, in order to obtain good photographic properties, it is necessary that the ratio of x to y of the aforesaid general Formula II is /5 to 30/70.

The copolymer of vinyl alcohol and cyanoethylvinyl ether or the copolymer of vinyl alcohol and an alkyl vinyl ether used in this invention is soluble or dispersible in a colloidal state in water, an alkali or organic solvents.

The turbidity-preventing effect of the copolymer of vinyl alcohol and cyanoethylvinyl ether or the copolymer of vinyl alcohol and an alkylvinyl ether used in this invention is influenced only slightly by the degree of polymerization, a copolymer having any degree of polymerization can be employed effectively in this invention if it is a liquid or a solid having a high boiling point, and is soluble in aqueous solution and alkali, and preferably in organic solvents. However, the emulsion characteristics are affected by the degree of polymerization and accordingly it is preferred that the degree of polymerization range from 400 to 2000.

As a binder for the emulsion used for the color photographic light-sensitive element of this invention there may be employed a suitable protective colloid such as gelatin, polyvinyl alcohol, a derivative of polyvinyl alcohol, polyaclylamide, a derivative of polyacrylamide, a celluose derivative, casein, an alginate and the like, but among them gelatin is most preferable.

As the organic solvent utilized for incorporating the copolymer of this invention in photographic emulsions, there may be employed alcohols, such as, methanol, ethanol, isopropanol, etc.; ether alcohols, such as Cellosolve, Carbitol, etc.; esters such as ethyl ether, dioxane, tetrahydrofuran, etc.; ketones such as acetone, methyl athyl ketone, etc.; amides such as lactams, dialkylcarbamides, etc., and the like.

The amount of the copolymer of vinyl alcohol and vinyl pyrrolidone or the copolymer of vinyl alcohol and cyanoethylvinyl ether or a copolymer of vinyl alcohol and alkyl vinyl ether used in this invention to be incorporated in a photographic silver halide emulsion depends upon the kind and the amount of the coupler in the emulsion. In general, the color turbidity-preventing effect reaches a maximum when about 5% by weight is added based on the weight of gelatin present in the emulsion layer although more or less amounts may of course be employed. However, when the amount of the copolymer is over 20% by weight of the gelatin, the coupling efficiency and the quality of layers are reduced. Hence, amounts of from about 1 to about 15% by weight are suitable in general.

The amount of the partially saponificated polyvinyl alcohol used in this invention, in the case of adding the copolymer to a photographic silver halide emulsion, is influenced by the kind and the'amount of coupler in the emulsion but in general the color turbidity-preventing effect reaches maximum when about 5% by weight is added based on the weight of gelatin in the emulsion although other amounts may be employed. However, if the amount of the copolymer is larger than 20% by weight of the gelatin, the coupling effect and the quality of coating are degraded. Thus, the amount of the copolymer is suitably 110% by weight.

The invention can be applied to color photographic l ght-sensitive elements contain g y o p er b t most effectively to color photographic light-sensitive elements containing the following oil-soluble couplers:

Coupler 1.--4-benzoylacetamido-N-butyl-N- octylbenzamide (C H2)1C H3 Coupler 2.l-hydroxy-4chloro-dodecyl-Z-naphthamide on @Ucomnomhom Coupler 3.1( 2,4,6-trichlorophenyl)-3-[3-(N-butyltetradecanamido) -propanamide]py1azoline-5-on CH3(CH2) 2C O NCHzCHzCONH-CCH2 CHa(CH2)a The color turbidity-preventing polymer used in this invention may be incorporated in a coating composition for photographic layers at any stage of preparation, for example, during dispersing of the coupler, mixing the emulsion or just before applying the coating composition to a support, but it is most preferable to incorporate it at the stage of dispersing the coupler.

The aforesaid copolymer may be most effectively incorporated in a silver halide emulsion layer but may also be effectively incorporated in at least one contiguous layer, such as the antihalation layer, insulating layer, filter. layer, or a protective layer. In the latter case, the copolymer may be incorporated in the layer in an amount of up to 50% by weight of the gelatin therein without having any adverse influences on the physical properties of the layer, the coupling efliciency of couplers, etc.

The invention will be explained in more detail by the following examples although the invention shall not be limited to them in any way.

EXAMPLE 1 To a mixture of ml. of an aqueous 10% gelatin solution and 2 ml. of a 10% aqueous solution of sodium alkylbenzene sulfonate was added 10.0 ml. of a 5% aqueous solution of a copolymer of vinyl alcohol and vinyl pyrrolidone (JC/)=90Z10, n==1000) with stirring. A solution of 3.0 g. of Coupler I mentioned above in a mixed solvent of 2.0 ml. of dibutyl phthalate and 3.0 ml. of ethyl acetate was added to the solution prepared as above. The mixture was stirred at -50 C. by means of a high speed homoblender intermittently five times each for 3 minutes with one minute interruption to provide a dispersion of coupler and polymer in a gelatin solution.

The entire amount of the emulsified dispersion was mixed with a gelatino silver halide emulsion containing 7.0 g. of silver bromide and 5.0 g. of gelatin and the resulting mixture was applied to a film base and dried. The light-sensitive film thus prepared was exposed and subjected to photographic processings, such as, color development, water washing, potassium ferricyanide-bromide bleaching, and fixing.

For determining the extent of yellow image turbidity, the red optical density of the yellow image was measured with the density-ratio of residual silver halide to yellow dye image is highest in red, the results of which are shown in Table 1 shown below.

EXAMPLE 2 A photographic light-sensitive film was prepared as in Example 1 while using 2.4 g. of Coupler 2 mentioned above instead of the coupler used in Example 1. The light-sensitive layer thus formed exposed and subjected to color photographic processings, such as, color development, water washing, potassium ferricyanide-bromide bleaching, etc.

For determining the extent of cyan image turbidity, the blue optical density of the dye image was measured, the results of which are shown in Table 1 shown below.

EXAMPLE 3 A photographic light-sensitive emulsion layer was prepared as in Example 1 while using Coupler 3 mentioned above instead of the coupler used in Example 1. The light-sensitive layer thus prepared was exposed and subjected to color photographic processings such as color development, water washing, potassium ferricyanide-bromide bleaching, etc.

For determining the extent of the magenta image turbidity, the red optical density of the dye image was measured, the results of which are shown in Table 1.

TABLE 1 Red Blue optical optical density density Coupler copolymer Example:

1 Coupler 1 (yellow) None (control)- do Added 2 Couple1'2 (cyan) None do Added 3 Coupler?) (magenta).- None do Added The table shows that in any cases of using the yellow, cyan and magneta couplers, the color turbidity measured by the optical density in an unnecessary wavelength region for the respective dye proper was markedly reduced by incorporating in the color photographic silver halide emulsions containing them the copolymer of vinyl alcohol and vinyl pyrrolidone.

EXAMPLE 4 A photographic light-sensitive film was prepared as in Example 1 using the following copolymers set forth in Table 2 instead of the copolymer used in Example 1. The light-sensitive layer thus prepared was exposed and subjected to photographic processings as in Example 1.

To determine the extent of the yellow image turbidity, the red optical density of the yellow image was measured with the relative value at the point where the blue optical density of the yellow image was 1.0.

As shown above in Table 2, the color turbidity of the yellow image measured in terms of the red optical density in the case of using the copolymer of this invention was much lower than that of other copolymers.

The red optical density in the case of using copolymer (4) was considerably higher than that of the control.

Samples of the photographic light-sensitive films corresponding to the above comparative Table 1, furthermore, clearly illustrate that the color turbidity was markedly reduced by incorporating copolymers of the present invention in the color photographic silver halide emulsions and by improving the poor silver bleaching thereby.

EXAMPLE Color photographic layers were prepared as in Example 1 while using, instead of the copolymer of vinyl alcohol and vinyl pyrrolidone (x/y=90:10, 11:1000), the following copolymers respectively:

(1) Copolymer of vinyl alcohol and vinyl pyrrolidone (monomer ratio: (x/y was 80:20, n=500),

(2) (x/y was 70:30, n=1000-), and

(3) (x/y was 40:60, n=2000).

The light-sensitive layers were exposed and subjected to color photographic processings such as color development, water washing, potassium ferricyanide-bromide bleaching, etc.

For determining the extent of the yellow image turbidity, the red optical density of the dye image was measured, the results of which are shown in the following table:

TABLE 3 Red optical Copolymers: density 1 0.26

3 0.17 None (control) 0.61

As shown above in the table, the image turbidity in terms of the red optical density in the case of using the color turbidity-preventing agent of this invention was much lower than that of the control.

EXAMPLE 6 A comparison with respect to the development rate suppressing degree was made between the photographic light-sensitive layers of this invention and known vinyl pyrrolidone-vinyl acetate (monomer ratio 7:3, 21:1000) copolymer (Copolymer 5) and vinyl pyrrolidone-styrene (7:3) copolymer (Copolymer 6) shown in Japanese Pat. 705/66.

That is, these light-sensitive films were exposed and the ratio of the density when developed for 3 minutes to the density when developed for 15 minutes was measured, the results of which are shown in the following table, in which the larger the ratio, the lower the development suppression.

TABLE 4 Light sensitive layer: Density ratio Example:

3 0.54 4-(1) (copolymer 1) 0.47 4-(2) (copolymer 2) 0.42 4-(3) (copolymer 3) 0.39 Comparison 5-(4) (copolymer 5) 0.20 5-(5) (copolymer 6) 0.23 Control (no copolymer) 0.56

From the above table, it is clear that the development suppression was much lower in the case of employing the vinyl alcohol-vinyl pyrrolidone copolymer of this invention than the case of employing the copolymer shown i p se Pat. No. 705/66,

8 EXAMPLE 7 Instead of adding the vinyl alcohol-vinyl pyrrolidone copolymer (x/y=/ 10, 21:1000), at the stage of dispersing the coupler to a coupler-dispersion as in Example 1, 15 ml. of 2% by weight of an aqueous solution of the copolymer Was added directly to a gelatino silver halide emulsion containing 6.0 g. of silver bromide, 6.0 g. of gelatin and 88 g. of water. Then, the emulsion was mixed with an emulsified dispersion of the yellow coupler and gelatin and the resulting mixture was applied to a film base and dried. The light-sensitive layer thus prepared was exposed and subjected to color photographic processings such as color development, water Washing, potassium ferricyanide-bromide bleaching, etc. For determining the extent of yellow image turbidity, the red optical density of the dye image was measured, the results of which are shown in Table 5.

TABLE 5 Copolymer: Red optical density Vinyl alcohol-vinyl pyrrolidone copolymer (x/y:9/l) 0.14 None 0.52

As shown in the above table, the red optical density of the photographic film of this invention was remarkedly reduced by the copolymer of the present invention.

Further, from the results it is clear that the copolymer of this invention was added effectively in either the coupler-emulsifying stage or emulsion mixing stage.

EXAMPLE 8 'In a mixture of 2.0 ml. of di-n-butyl phthalate and 3.0 ml. of ethyl acetate was dissolved at an elevated temperature 3.0 g. of a yellow coupler, Coupler 1 mentioned above and the resultant solution was added to a mixture of 10.0 ml. of a 5% aqueous solution of a copolymer of vinyl alcohol and cyanoethylvinyl ether (at/3 :88:12, n=1000) and 20 ml. of an aqueous 10% gelatin solution containing 2 ml. of a 10% aqueous solution of sodium alkylbenzene sulfonate. The mixture was stirred at 4050 C. by means of a high speed homoblender five times each for 3 minutes with one minute interruption to provide an emulsified dispersion of the coupler and the polymer in gelatin solution.

The whole amount of the dispersion was mixed with a gelatino silver halide emulsion containing 5.0 g. of gelatin and 7.0 g. of silver bromide and the resulting mixture ,was applied to a film based and dried. The lightsensitive color film thus prepared was exposed and subjected to color photographic processings such as color development, water washing, bleaching by potassium ferricyanide and bromide, etc.

The extent of yellow turbidity is determinable by meas uring the red optical density of the yellow image, since the density ratio of residual silver image to yellow dye-image is highest in red. The results are shown in Table 6 shown below.

EXAMPLE 9 A color photographic light-sensitive emulsion layer was prepared as in Example 7 but using 2.4 g. of a cyan coupler. Coupler 2 mentioned above instead of the coupler used in Example 8 and after exposure, the lightsensitive layer was subjected to color photographic processings such as color development, water washing, potassium ferricyanide-bromide bleaching, etc.

The extent of cyan dye image turbidity is able to be determined by measuring the blue optical density of the cyan image. The results are shown in Table 6 shown below..

EXAMPLE 10 A color photographic light-sensitive emulsion layer was prepared as in Example 8 but using 4.3 g. of a magenta coupler, Coupler 3 mentioned above instead of the coupler used in Example 8 and after exposure, the

TABLE 6 Red opti- Blue opti- Coupler Copolymer cal density cal density None Coupler 1 (yellow) .Do

Do- "I AddedII.--

Table 6 shows that by incorporating the color turbiditypreventing copolymer of this invention in the color photographic silver halide emulsion containing the coupler, the formation of color turbidity measured by the optical density in an unnecessary wave length regions to the respective dye proper was effectively prevented in each case.

EXAMPLE 11 A color photographic light-sensitive film was prepared as in Example 8 while using, instead of the copolymer of vinyl alcohol and cyanoethylvinyl ether (x/3 :88:12, 12:1000), each of the following copolymers:

Copolymer of vinyl alcohol and cyanoethylvinyl ether:

(1): (x/y=80/20, n 2000),

(2): (x/y:70/30, 11::1000), (3): (x/y=60/40, 11:2000), and (4): (x/y=40/60, 11:500).

After exposing the light-sensitive layer, the layer was subjected to color photographic processings such as color development, water Washing, potassium ferricyanide-bromide bleaching, etc.

For determining the extent of yellow image turbidity, the red optical density of images thus obtained, the rcsults of which are shown in Table 7.

TABLE 7 copolymers: Red optical density 1 0.31

4 0.33 None (control) 0.61

(Coupler 1 (yellow) was used).

As shown in the above table, the image turbidity measured in terms of the optical density in the case of using the color turbidity-preventing copolymer of this invention was much lower than that of the control cases.

EXAMPLE 12 A comparison with respect to the development rate suppressing degree was made between the photographic lightsensitive layers of this invention, each containing one of the copolymers of viny alcohol and cyanoethylvinyl ether shown in Examples 8-11, and photographic lightsensitive layers, each containing one of the color turbidity preventing agents disclosed in Japanese patent publication No. 705/66 shown below:

Control copolymer 5: Copolymer of vinylpyrrolidione and vinyl acetate (monomer ratio 7:3, 11:1000), and

Control copolymer 6: Copolymer of vinylpyrrolidone and styrene (monomer ratio 7:3).

The photographic light-sensitive layers shown in Examples 8-11 and the control photographic light-sensitive layers prepared above were exposed and subjected to a color development. The development rate was measured in terms of the density obtained in three minutes of development compared with that obtained in fifteen minutes. In the table, the larger the density ratio, the faster the development rate, or the lower the development suppressing tendency.

10 TABLE 8 Light sensitive layer:

Examples: Density ratio 7 0.54 8 0.49 9 0.49 10 (copolymer 1) 0.51 10 (copolymer 2) 0.59 10 (copolymer 3) 0.56 10 (copolymer 4) 0.50 Control 11 (copolymer 5) 0.20 11 (copolymer 6) 0.23 Control (no copolymer) 0.56

From the table, it will be clearly understood that the color turbidity-preventing copolymers used in this invention have remarkedly lower development suppressing tendency than the turbidity-preventing copolymers shown in the specification of Japanese patent publication 705/66.

EXAMPLE 13 Color photographic light-sensitive layers were prepared as in Example 1 While using, instead of the copolymer of vinyl alcohol and cyanoethylvenyl ether used in Example 8, the following copolymers of vinyl alcohol and alkylvinyl ethers;

Copolymer 8: Copolymer of vinyl alcohol and ethylvinyl ether (x/y=/20, 11:1000),

Copolymer 9: Copolymer of vinyl alcohol and propylvinyl ether (x/ y=80/ 20, 11:1000), and

Copolymer 10: Copolymer of vinyl alcohol and butyl- Vinyl ether (x/y=80/20, n=l000).

The light-sensitive layers Were exposed and subjected to color photographic processings such as color development, water washing, potassium ferricyanide-bromide bleaching, etc.

For determining the extent of yellow image turbidity, the red optical densities of the samples were measured, the results of which are shown in Table 9.

TABLE 9 copolymers: Red optical density 8 0.42 9 0.37 10 0.40 None (control) 0.61

(Coupler 1 (yellow coupler was used.)

As shown in the above table, the red optical density in the case of using the color turbidity-preventing copolymer of this invention was much lower than that of the control case.

EXAMPLE 14 To a gelatino silver halide emulsion contianing 6.0 g. of silver bromide, 6.0 g. of gelatin, and 88 g. of water was added directly 15 ml. of 2% by weight of an aqueous solution of the copolymer of vinyl alcohol and cyanoethyl-vinyl ether (x/y=88/ 12, n=1500) without adding it at the emulsification stage of coupler as in Example 8. The gelatino silver halide emulsion containing the copolymer was mixed with a dispersion of the coupler and gelatin and. the resulting emulsion applied to a film followed by drying. The photographic light-sensitive layer was exposed and subjected to color photographic processings such as color development, water washing, potassium ferricyanide-bromide bleaching, etc.

For determining the extent of yellow turbidity, the red optical density was measured, the results of which are shown below.

TABLE 10 Copolymer: Red optical density Copolymer of vinyl alcohol and cyanoethylvinyl ether (88:12) 0.16

None 0.52

(Coupler 1 (yellow coupler) was used.)

1 1 As shown in Table 10, the red optical density was remarkedly reduced by the copolymer of the present invention. Further, from the results, it will be understood that the copolymer of this invention was efifective irrespective of the stage of its addition to the system.

EXAMPLE 15 In a mixture of 2.0 m1. of di-n-butyl phthalate and 3.0 ml. of ethyl acetate was dissolved by heating 3.0 g. of Coupler 1 (yellow coupler) mentioned above. Further 0.3 g. of the partially saponified polyvinyl alcohol (x/y=88/l2, degree of polymerization 11:500) was dissolved in ml. of an aqueous 10% by weight gelatin solution containing 2.0 ml. of a 10% aqueous solution of sodium alkylbenzene sulfonate. After mixing the two solutions prepared above, the mixture was stirred at 40- 50 C. by means of a high speed homoblender five times each for 3 minutes with one minute interruption to provide a dispersion of the coupler and the polymer in a gelatin solution.

The whole amount of the emulsified dispersion was mixed with a gelatino silver halide emulsion containing 6.0 g. of silver bromide, 6.0 g. of gelatin and 88 g. of water and the resulting emulsion was applied to a triacetyl cellulose film followed by drying.

The light-sensitive film thus prepared was exposed and subjected to color photographic processings at 24 C., such as, color development, water washing, potassium ferricyanide-bromide bleaching, and fixing.

For determining yellow image turbidity, the red optical density of the color image was measured, the results of which are shown in Table 11 shown 'below.

EXAMPLE 16 A color photographic light-sensitive emulsion layer was prepared as in Example 15 but using 2.4 g. of Coupler 2 (cyan coupler) mentioned above instead of the coupler used in Example 15. The light-sensitive layer was exposed and subjected to color photographic processing such as color development, water washing, potassium ferricyanide-bromide bleaching, and fixing. For determining the extent of cyan turbidity, the blue optical density of the color image was measured, the results of which are shown in Table 11 shown below.

EXAMPLE 17 TABLE 11 Red Blue optical optical Coupler Copolymer density density Example:

15 Coupler 1 (yellow) None 0. 52 do Added 0.10

16 Coupler2 (cyan) None 0.83 do Added 0.12

17 Coupler 3 (magenta) None 0. 56 d0 Added 0.30

EXAMPLE 18 Color photographic light-sensitive layers were prepared as in Example 15 while using instead of the partiallysaponified polyvinyl alcohol (x/y=88/l2, n=500) each of the following partially-saponified polyvinyl alcohols:

(l) (x/y=80/20, 11:500), 2 (x/y==88/l.2., @1000),

12 (3) (x/y=88/l2, 12:1700), and (4) (x/y=/5, 11:500).

The light-sensitive layers thus prepared were exposed and subjected to color photographic processings, such as, color development, water washing, potassium ferricyanidebromide bleaching, and fixing.

For determining the extent of the yellow image turbidity, the red optical density of yellow images are measured, the results of which are shown in the following table.

TABLE 12.

Copolymer (partially-saponified Red optical polyvinyl alcohol): density (1) 0.38

(4) 0.41 None (control) 0.61

As shown in the above table, the image-turbidity measured in the term of the red optical density in the case of using the color turbidity preventing polymer of this invention was much lower than that of the control case.

EXAMPLE l9 Photographic light-sensitive films for comparison were prepared as in Example 15 using Coupler 1 (yellow) and the known vinylpyrrolidonevinyl acetate (monomer ratio 7:3, 11:1000) copolymer (Copolymer 5) and vinylpyrrolidonestyrene (7:3) copolymer (Copolymer 6) described in Japanese patent publication No. 705/66 and compared with the photographic light-sensitive films containin g the partially saponified vinyl alcohols of this invention prepared in Examples 15-18 about development suppression.

That is, these light-sensitive films were exposed and the ratio of the density when developed for 3 minutes to the density when developed for 15 minutes were measured, the results of which are shown in Table 13, in which the larger ratio, the lower the development suppression.

TABLE 13 Light-sensitive layer:

Examples: Density ratio 15 0.52 16 0.54 17 0.48 18 (polymer 1) 0.53 18 (polymer 2) 0.48 18 (polymer 3) 0.51 18 (polymer 4) 0.57

Comparative:

(Polymer 5 0.20 (Polymer 6) 0.24

Control (no polymer) 0.56

From the table, it is clear that the use of the color turbidity preventing polymer used in this invention have a remarkably lower development suppression tendency than the turbidity-preventing polymers disclosed in Japanese patent publication No. 705/66.

XAMPLE 20 Instead of adding the partially saponified polyvinyl alcohol (x/y=88/12, 11:500) at the stage of dispersing the coupler as in Example 15, 15 ml. of 2% by weight of an aqueous solution of the polymer was added directly to a gelatino silver halide emulsion containing 6.0 g. of silver bromide and 6.0 g. of gelatin. Thereafter, the gelatino silver halide emulsion containing the polymer was mixed with an emulsified dispersion of the yellow coupler (Coupler 1) and gelatin and the resulting emulsion was applied to a film base and dried. The photographic light-sensitive layer was exposed and subjected to color photographic processings such as color development, water washing, potassium ferricyanide-bromide bleaching and fixing. For

13 determining the extent of yellow image turbidity, the red optical density of the color image was measured, the results of which are shown in Table 14.

TABLE 14 Color turbidity preventing agent: Red optical density Partially saponified polyvinyl alcohol ('x/y=88/12, 11:500) 0.13 None (control) 0.52

EXAMPLE 21 The relation between the polymerization degree and the effect in promoting silver-bleaching is illustrated hereinafter.

Samples were prepared as in Example 14. After that, they were exposed and subjected to color photographic processings such as developing, bleaching, fixing and drying treatments. The red optical density of the yellow image turbidity was measured to determine the extent of the yellow image turbidity with a variety of polymers having different polymerization degrees. The results obtained are shown in Table 15 below.

NOTE.PVA Polyvinyl alcohol; PVI Polyvinyl pyrrolidone.

As shown above in Table 15, the red optical density of the yellow image gave the lowest value in the case of using a copolymer of this invention having a polymerization degree of 11:800. This represents the lowest color turbidity of the yellow image and the highest effect for the promotion of silver-bleaching. In the case of copolymers having a. polymerization degree outside the region of from 400 to 2000, on the other hand, this eifect was markedly decreased.

The above described procedures were repeated with copolymers of polyvinyl acetate or polyvinyl cyanoethyl and polyvinyl alcohol with the fresh film containing the copolymers being allowed to stand at a high humidity percentage (50 C. 80%, 2 days). The results obtained are shown in Tables 16 and 17 below.

As can be seen from the results shown in Tables 16 and 17, with a copolymer having a polymerization degree of less than 400 the effect of the promotion of silverbleaching is decreased due to the stickiness of the copolymer on the emulsion particles, such as silver halide declines, namely an increase of the seceding effect.

14 EXAMPLE :22

This example shows an embodiment in which the copolymer according to the present invention is incorporated in the antihalation layer.

The copolymers used in this example were as follows:

(1) Vinylalcohol-vinylpyrrolidene copolymer (x/y=8/2, n=500),

(2) Partially saponified polyvinyl alcohol (3 Vinylalcohol-ethylvinylether (x/y=8/2, n=500), and

(4) Vinylalcohol-cyanoethylvinylether (x/y=8/2, n=500).

Each of four emulsion sols, prepared by separately adding 15% by weight of each of copolymers (1) to (4) according to the present invention to the emulsions. containing colloidal silver for antihalation based on the weight of the gelatin, and another emulsion sol without any of the above copolymers were separately added with a hardening agent and a coating assistant to prepare five coating liquids for an antihalation layer.

Preparation of the red-sensitive emulsion 2.4 g. of Coupler 2 (cyan coupler) described above was added to a mixed solution of 2.0 ml, of dibutyl phthalate and 3.0 ml. of ethyl acetate, and heated to dissolve, and was added to 10 ml. of 10% by weight of an aqueous gelatin solution containing 2.0 ml. of 10% sodium alkylbenzene sulfonate, and stirred at high speed using a homoblender at 50 C. for 10 minutes to obtain a dispersion of Coupler 2 emulsified in an aqueous gelatin solution.

The entire quantity of this emulsion dispersion was mixed with a gelatino silver halide emulsion containing 6.0 g. of silver bromide, 6.0 g. of gelatin, 5.0 ml. of a 0.1% methanol solution of anhydro-5,5'-dichloro-3',9- diethyl-3-(6-sulfobutyl)-'selenacarbocyanine hydroxide, as a spectral sensitizing dye for red light, and 88 ml. of water, added with a hardening agent and a coating assistant to prepare a coating liquid for a. red sensitive emulsion.

This coating liquid was coated on each of the above five antihalation coating layers at a thickness of 3.0 1. and dried to prepare five samples coated with a red-sensitive emulsion containing a cyan coupler on five antihalation layers, four of which contain copolymers (1) to (4) according to the present invention on a support and the fifth not containing such a copolymer.

These photographic light-sensitive elements were exposed and subjected to the conventional color developing treatments of color development, washing with water, bleaching with potassium ferricyanidebromide, and fixing, etc. The treating temperature was 24 C.

In order to compare the turbidity (poor silver-bleaching) of the cyan colored image, the blue optical density was measured. The results obtained are shown in Table 18.

That is, the photosensitive elements containing the copolymers according to the present invention are markedly lower in blue optical density value in comparison with the material not having such a copolymer and the cyan colored image is lower in color turbidity and therefore extremely preferred.

EXAMPLE 23 This example shows an embodiment in which the copolymer according to the present invention is incorporated in an intermediate layer.

The copolymers used in this example were the same as those used in Example 22.

The cyan color emulsion without any copolymers according to the present invention and, which was prepared in the same manner as in Example 22, was coated on a support and dried to the thickness of 3.0;.

On the other hand, each of the four emulsions prepared by adding 30 ml. of a 2% aqueous solution of the copolymers (1) to (4) as in Example 22 to 100 g. of 4% by Weight, of an aqueous gelatin solution and another emulsion without any ofthe above copolymers were separately added with a hardening agent and a coating assistant to prepare coating liquids for an intermediate layer.

These five coating liquids were separately coated on a red sensitive emulsion as prepared in Example 22 so that the dried film is 2.0/L in thickness, and were dried.

Preparation of green sensitive emulsion 2.0 g. of the Coupler 3 (magenta) described above was dissolved in 3.0 ml. of tricresyl phosphate and the resulting solution was emulsified in 10 g. of 10% by weight of an aqueous gelatin solution using dodecyl sodium sulfate as a dispersing agent to prepare a dispersion.

The entire amount of this emulsified dispersion was mixed with a gelatino silver halide photographic emulsion containing 6.0 g. of silver bromide, 6.0 g. of gelatin, 5 ml. of a 0.1% solution of 3,3,9-triethyl-5,5'-diphenyl-oxacarbocyanine iodide in methanol, as a green spectral sensitizing dye, and 88 ml. of water, and was added with a hardening agent and a coating assistant.

The green sensitive silver halide photographic emulsion sols so prepared were separately coated on the abovedescribed intermediate layers and dried to obtain five types of photosensitive elements, four of which contain separately copolymers (1) to (4) described above in the intermediate layer, and the fifth element Without such a copolymer.

In order to examine the cyan image and the magenta image of the above photosensitive elements with respect to color turbidity, each was exposed in green light and was exposed in red light subjected to conventional color developing treatments such as color developing, washing with water, bleaching with potassium ferricyanide-bromide and fixing, etc.

The blue optical density was measured to examine the turbidity of the cyan colored image, and the red optical density was measured for the same purpose as the above, except for the magenta image.

The results obtained are shown in Table 19.

TABLE 19 Red optical Blue optical density density copolymer:

From Table 19 it is obvious that photosensitive elements containing copolymers (1) to (4) according to the present invention are markedly lower in optical density value and have less color turbidity in the cyan colored image (measurement of blue optical density) and the magenta colored (measurement of red optical density) than the element without such a copolymer.

EXAMPLE 24 sol for a yellow filter containing 0.2 g. of colloidal silver and 4 g. of gelatin and another emulsion without having containing any such copolymers were added with a hardening agent and a coating assistant to make coating liquids for a yellow filter.

These five coating liquids were separately coated on the above green sensitive photographic emulsion layers and dried to prepare five photosensitive elements.

These five photosensitive elements were exposed and subjected to the conventional color developing treatments of color developing, washing with water, bleaching with potassium ferricyanide-bromide, and fixing, etc.

The red optical density of the magenta colored image was measured for color turbidity. The results obtained are as shown in Table 20.

As shown by the results given in Table 20, the photosensitive elements containing copolymers (1) to (4) according to the present invention are markedly lower in red optical density value and have less in turbidity of magenta colored image than the element not having such a copolymer.

EXAMPLE 25 This example shows an embodiment in which the copolymer according to the present invention is incorporated in the protective layer.

3.0 g. of the Coupler 1 (yellow coupler) described above dissolved in 2.0 ml. of dibutyl phthalate and 3.0 ml. of ethyl acetate were added to 20 ml. of 10% by weight gelatino aqueous solution containing 2.0 ml. of aqueous solution of sodium alkyl benzene sulfonate, and blended using a homoblender of 50 C. for 10 minutes to prepare an emulsified dispersion.

The entire amount of this emulsified dispersion was mixed with a gelatino-silver halide emulsion sol containing 7.0 g. of silver bromide and 5.0 g. of gelatin, and added with a hardening agent and a coating assistant.

The silver halide photographic emulsion containing this yellow coupler was coated on a support at a dried thickness of 4.0a and dried.

0n the other hand, four types of emulsion sols prepared by separately adding copolymers (1) to (4) as used in Example 22 to g. of 4% by weight, of an aqueous gelatino solution, one prepared by adding 30 ml. of 2% by weight of polyvinyl pyrrolidone-acrylic acid (monomer ratio 7:3) thereto as a comparative sample, and another emulsion sol not containing such a copolymer were separately added with a hardening agent and a coat ing assistant to prepare a coating liquid for a protective layer.

These coating liquids for the protective layer were separately coated on a photographic emulsion layer containing the above yellow coupler, and dried.

These six photosensitive materials were exposed and subjected to conventional color developing treatments such as color developing, washing with water, bleaching with potassium ferricyanide-bromide, and fixing.

The red optical density of this yellow colored image was measured for its turbidity. The results are shown in Table 21.

As shown in Table 21, the photosensitive elements containing copolymers (1) to (4) are markedly lower in red optical density value and had less turbidity of yellow image than the others.

From the results given above in the examples it can be seen that a photographic light-sensitive element containing a member selected from the group consisting of a copolymer of vinyl alcohol and vinyl pyrrolidone of the formula above described with an x/y ratio ranging from 95/5 to 60/40 and a degree of polymerization of 400 to 2000; a partially saponificated polyvinyl alcohol of the formula above described with an x/ y ratio ranging from 95/5 to 70/30 and a degree of polymerization of 400 to 2000; and a copolymer of vinyl alcohol and cyanoethyl vinyl ether or an alkyl vinyl ether having the formula above described with an x/ y ratio ranging from 95/5 to 30/70 and a degree of polymerization of from 400 to 2000; in one of the layers of the photographic light sensitive element possesses markedly reduced color turbidity due to improvement of silver removal or silver bleaching.

What is claimed is:

1. In a color photographic light-sensitive element comprising a support bearing thereon at least one oil-soluble coupler-containing silver halide photographic emulsion layer, a protective layer, insulating layers, filter layers, and a antihalation layer, the improvement comprising incorporating additionally in said silver halide photographic emulsion layer, in a layer contiguous to said silver halide photographic emulsion layer or in said silver halide photographic emulsion layer and said layer contiguous to said silver halide photographic emulsion layer of a polymer selected from the group consisting of:

(1) a copolymer of vinyl alcohol and vinyl pyrrolidone represented by the general formula wherein the ratio of x to y ranges from 95/5 to 40/60 and n is a positive integer from 400 to 2000,

(2) a partially saponified polyvinyl alcohol represented by the general formula L\ on}, OCOCHZ/y-in wherein the ratio of x to y ranges from 95/5 to 70/30 and n is a positive integer of from 400 to 2000, and

(3) a copolymer of vinyl alcohol and a vinyl ether represented by the general formula wherein R represents a member selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms and -CH CH CN, the ratio of x to y ranges from 95/5 to 30/70 and n is a positive integer of from 400 to 2000.

2. The color photographic light-sensitive element as claimed in claim 1, wherein said compound represented by general Formula II is selected from the group consisting of a partially saponified polyvinyl alcohol wherein the x/y ratio is 88/12 and n is 500; a partially saponified polyvinyl alcohol wherein the x/y ratio is /20, and n is 500; a partially saponified polyvinyl alcohol wherein the x/y ratio is 88/12 and n is 1000; a partially saponified polyvinyl alcohol wherein the x/y ratio is 88/12 and n is 1700; and a partially saponified polyvinyl alcohol wherein the x/y ratio is 95/5 and n is 500.

3. The color photographic light-sensitive element as claimed in claim 1, wherein said copolymer represented by general Formula III is a copolymer of vinyl alcohol and cyanoethylvinyl ether.

4. The color photographic light-sensitive element as claimed in claim 3, wherein said. monomer ratio is selected from the group consisting of 88/12, 8/2, 7/ 3, 6/4, and 4/ 6.

5. The color photographic light-sensitive element as claimed in claim 1, wherein said copolymer is selected from the group consisting of a copolymer of vinyl alcohol and ethylvinyl ether, a copolymer of vinyl alcohol and propylvinyl ether, and a copolymer of vinyl alcohol and butylvinyl ether.

6. The color photographic light-sensitive element as claimed in claim 1 wherein said coupler is selected from the group consisting of 4-benzoylacetamido-N-butyl-N- octylbenzamide, 1 hydroxy-4-chloro-N-dodecyl-2-naphthamide, and 1-(2,4,6-trichlorophenyl) 3 [3-(N-butyltetradecaneamido)-propanamide]pyrraZolidone-5-one.

7. The color photographic light-sensitive element as claimed in claim 1 wherein said polymer is incorporated in said silver halide photographic emulsion layer and at a level of from about 1 to about 15% by Weight based on the weight of the emulsion for said copolymer of vinyl alcohol and vinyl pyrrolidone, at a level of from about 1 to about 10% by weight based on the weight of the emulsion for the partially saponified polyvinyl alcohol, and at a level from about 1 to about 15% by weight based on the weight of the emulsion for the copolymer of vinyl alcohol and vinyl ether.

8. The color photographic light-sensitive element as claimed in claim 1, wherein said polymer is incorporated in a layer contiguous to said silver halide photographic emulsion layer at a level of up to 50% by weight based on the weight of the emulsion.

9. The color photographic light-sensitive element of claim 1, wherein the ratio of x to y in said copolymer of vinyl alcohol and vinyl pyrrolidone ranges from 10 to 80/20 and wherein the ratio of x to y in said partially saponified polyvinyl alcohol ranges from 90/ 10 to 80/ 20.

10. The color photographic light-sensitive element of claim 1, wherein said emulsion layer containing said oilsoluble coupler contains an oily-solvent having a high boiling point.

11. The color photographic light-sensitive element of claim 10, wherein said oily-solvent is dibutylphthalate, or tricresylphosphate.

References Cited UNITED STATES PATENTS 2,893,867 7/1959 Dawson et a1. 96-97 2,414,208 1/ 1947 Murray 96-414 3,479,186 11/1969 Taylor et a1. 96114 3,516,831 6/1970 Wolf et a1 96-100 2,286,215 6/1942 Lowe 96--114 RONALD H. SMITH, Primary Examiner US. Cl. XR. 

